Composite paving block



Nov. 1, 1932. L. F. HEWETT v 1,885,720

- COMPOSITE PAVING BLOCK Filed Oct. 29, 1929 M nn ' INVENTOR Lou/J f-Tflewezi ATTORN 5Y5 UNITED STATES" Patented Nov. 1, 1932 insane- LOUIS F. HEWETT, OF NEW YORK, N'. Y., .ASSIGN'OR TO HILDA E. HEWET'I, O13 7 BROOKLYN, NEW YORK oo urosrrn ravine BLOCK Application filed October 29, 1929. Serial No. 403,223.

This invention relates to paving blocks, and has for its object the provision of an improved paving block of the composite variety. More particularly, my invention is directed to the provision of an improved composite paving block, and a street paved with such'composite paving blocks. 7

There has been a marked need for a paving block which is at once durable, as to wearing qualities, uniform as to size, and relatively cheap to make, as well as one which can be rolled, as by a steam roller or other suitable roller. Numerous paving blocks of the composite kind have been made,but they, have almost uniformly been unsatisfactory for one reason or another; and have, therefore, met with little favor in actual practice.

An illustration of the use of such granite blocks and their specifications may advantageously be here considered. Blocks approximately 5 inches deep,-5 inches wide and 8-12 inches long are sometimes employed in the construction of highways. One city, for

V example, requires these specifications; which are considered very exacting, and can only be supplied at a premium: variationsof as much as inch in depth and in width are permitted when the granite blocks are to be 5 inches deep and 5 inches wide. This makes the use of-blocks of from 4% to 5 inches in depth and in width permissible. Variations of as much as 4 inches in length are permitted when the blocks are to be about 812 inches long.- Themore exacting the specifications, the more costly are the blocks; because of the expense required properly to dress the individual blocks to the uniform and desired dimensions.

. A concrete foundation is generally employed,'on which to place the granite blocks.

A cushiomsuch as a layer of sand, of about 1 inch thickness is generally interposed between the concrete base and the blocks. The blocks are placed on the cushion, and tampe-d into position so that their top surfaces are in substantially the same plane; or, at least, so that the tops ofthe blocks form a'relatively smooth road surface. Since the blocks may vary from one another in depth as much as 1 inch, accordingto the specifications outlined;

above, it will be apparent that when heavy traflic moves over the new pavement, the

blocks will move relatively to one another. 5

Thus, if a block 5 inches deep is adjacent to one 4% inches deep, the latter blockmay be pushed into the cushion a sufiicient distance to'cause the former block to protrude above, while the smaller block is depressed below the normal road surface. Since many such irregular blocks are employed, the pavement soon becomes irregular in its top surface; cor ners are exposed, and the road becomes noisy as traflic jostles over them. i

It is also apparent that when such irregular blocks are employed, it is practically impossible to provide uniform joints between blocks; that is, joints of uniform width. It is preferred that the joints be not more than inch wide; but such uniformity cannot be obtained When using blocks that vary in width as much as inch. Such joints are frequently'more than inch wide, and even amount to as much as 1 inch. Since the mor tar going into the joints is not as durable as the granite blocks, it is seen that the oints gradually wear down; leaving irregular depressions in the road surface.

The improved composite paving block of my invention, in its broadest aspect, comprises fragments of wearing materials secure ly imbedded in an appropriate matrix. By a suitable selection of these wearing fragments, and then securely and systematically 'imbed ding them in some appropriate matrix, as concrete, 1 am able to make a paving block which presents an unusually durable wearing surface, is uniform in size, and which can be rolled, and which is at the same time very cheap to make. f

In the present practice of my invention I make use of scrap fragments of granite, found at all granite quarries abundantly as waste, for the wearing materials, but fragments of any suitable stone'can be used. It is amatter of almost common'knowledge that quarried granite will practically always split into pieces having at least one relatively smooth and flat surface. This seems to be due to the inherent cellular structure ofthe graniteitis extremely hard and has unusual wearing strength. 1 place granite fragments, smooth face downward, of suitable size in a mold of desired dimensions, so that the edges surrounding the wearing surface of the individual fragments will be substantially close to one another, making a granite edge on all sides of the wearing surface. This can be done by a judicious selection of suitably sized fragments. An appropriate matrix, such as ordinary concrete, is then poured into the mold, between and upon the fragments, so that the fragments may be strongly and securely imbedded. If the blocks are relatively large, this concrete matrix is preferably reenforced, as with a wire-like basket.

If a composite paving block is made up in this manner, a block is obtained with the flat surfaces of the granite fragments exposed to the outside, all in one plane. These relatively smooth andfiat surfaces are thus seen to become the wearing surfaces of the block. In order that there may be no weakened portions along the contiguous edges of adjacently placed paving blocks, it is desirable that the granite fragments be placed along the outside edges of each composite paving block in such manner as to offer a substantially straight and continuous granite edge. It is, therefore, seen that a composite paving block of substantialy durability, as to wearing quality, exactness of size, and cheapness may thus be made. The materials employed are simple and relatively inexpensive.

These blocks may be of any desired shape or size. Thus, they might be shaped as a square, a rectangle, a triangle, a circle, etc. I prefer to have them shaped in the form of squares and triangles, the triangular shaped block being of such dimensions as to amount to one-half of a square block out diagonally from one corner to another. Wit-h blocks of this size and shape, a street or sidewalk, or

' any area which it is desired to pave, may be covered in staggered fashion, as will be more clearly shown below. The triangular blocks are then particularly well adapted to be fitted next to the curb.

Since a paving block of this kind lends itself readily to the use of granite or stone fragments, it will be seen that, since granite is found in a variety of colors, a pavement may be made of varied and pleasing colors. This will be a no inconsiderable feature, in the planning of streets in suburban districts, because it offers an escape from our otherwise drab and monotonously unicolored pavements.

The improved composite paving blocks of my invention are preferably made in an apparatus provided wih a plurality of molds, although single molds may be used. The molds arepreferablyso constructed that the paving block may come out in beveled form; That is to say, the sides of the block are so beveled or tapered that the wearing surface of the block will be relatively larger than the bottom of the block.

WVith this particular construct-ion of block, awater-proof packing material can be inserted in the interstices between adjacently placed blocks. Once the blocks are placed in final position, it is then impossible for this inverted wedge-like packing material to come out. Since the composite paving blocks themselvesare impervious to water, and this packing material does not absorb moisture, it is seen that the water from rains, snow and the like, may readily be drained to the side curbs.

My invention will be clearly understood by reference to the accompanying drawings, taken in conjunction with the following description, in which: 1 I Y Fig. 1 is a perspective view of a paved street, showing a transverse sectional view through a number of the paving blocks Fig. 2 is a perspective ,viewv of a single block; I a

Fig. 3 is a transverse sectional view on the line of Fig.2; I V

Fig. et is a perspective view'of a single mold; s V

Fig. 5 is a transverse sectional view on the line 5-5 of Fig. 4, showing a block in the mold;

rality of molds;

Fig. 7 is a part transverse sectional view 011 the line 77 of Fig. 6, and 7 Fig. Sis a perspective view of-a clamp used "to hold the mold [side members in position.

The composite paving block 10 is made up of wearing fragments 11 with their relatively fiatsurfaces exposed at the top of theblock for wearing purposes, all in one plane. These fragments are preferably selected with sufficient care so that each paving block may offeravery substantial part of itswearing surface in the form of these wearing fragments. be placed relatively close to one ,another,-so that the joints between them at thewearing surfaces are not more than about inch wide. The edges 12 of'the paving block are'substantia'lly made up of nothing but'edges of the wearing fragments. The corner fragments for the block are selected with care, so that each corner may be closely fittedgwith a fragment of'substantial size. I The individual Fig. 6 is a perspective.view showing a pl u.

Thatis to say, the fragments should wearing fragments are preferably of such curely imbedded in the matrix 13, such as the usual concrete.

In order to give the paving block added strength, I sometimes find it advisable to make use of a re-enforcer 14, which may be shaped somewhat as a wire basket, although anysuitable re-enforcing material may-be employed. This re-enforcing agent is placed approximately 1 inches from the bottom of the block.

' While it is not absolutely essential that the sides 15 of the paving blocks be beveled, I prefer such practice. In this manner the top of the paving block exposed to wearing is relatively larger than the bottom of the block. In the case of a 6 inch block, I prefer to have the bevel amount to approximately inch on each side. The paving blocks may be placed upon an old road bed 16, although a new road bed could, of course, be prepared. If this is done, it is preferred that a foundation bed of concrete first be laid. A cushion 17, such as of dry sand or dry sand and cement, of about 1 inch in thickness, is preferably V placed between the old road bed or foundation 16 and the paving blocks 10.

While the paving blocks may be put on the street in any desired manner, I prefer to have them placed in staggered fashion. That is to say, the blocks are so placed that the outside edges of the individual blocks will run diagonally acrossthe street or pavement. If this is done, it will be'seen that the wheels of moving traffic will not run parallelly along or over the edges of the paving blocks. Instead of that, the wheels will have to pass more directly across the edges of the paving block. In this manner the blocks will be protected at their weakest points.

By making use of square and triangularly shaped blocks, it is seen that the blocks may be all the more readily fitted over a road bed in such manner as to easily contact with thecurb 18; however, blocks of any desired shape may be employed.

As in the more usual road construction, it is preferred that the central portion of the road be raisedto a higher level than the sides of the road bed. In this manner the pave ment may be more readily drained of water and the like. Since the individualblocks are relatively small compared with the size of the street to be paved, and since the sides of the block are beveled in such manner as to make the bottom smaller'than the top, it is seen that these blocks offer no difficulty in giving the street the concaved surface necessary to makedraining of water effective. The blocks being uniform in size, they can be rolled by a heavy roller to get a smooth road surface. After the blocks are rolled into a smooth road surface, appropriatewafer-proof material 19 is packed between the sides of the individual blocks as they are laid on the streetfoundation. It is preferred that the blocks not be tightly placed against one another, but that a small amount of this plastic packing material be laid to separate the blocks.

In this mannerthe contraction and H expansion of the individual blocks will readpractically impossible for any moisture to seep down to the bottom of the paving block. Substantially all of the water and moisture should be drained toward the curb, from which it escapes inthe usual manner.

The mold or molds 20, of wood or metal and the like, are of 'the inverted type. That is to say, they are so constructed that the bottom of the mold 21 contacts with that part of the paving block which is to offer the wear ing surface, whereas, the bottom ofthe paving block will. then be on the top of the mold. The sides 22 are movable, as by the hinges 23, or stationary, while the bottom 21 is correspondingly stationary or movable. These side members are so cut at their ends that they may be moved together in such manner as to give the mold the desired beveled shape. c

In the case of an individual mold, as shown in Fig. 4, a member 24 may be provided about the entire mold in such manner that the wedges 25 may be hammered down between the stationary member part 24;.andthe movable member part 22, in order to cause the mold to come into the closed position. When it is desired to put the mold inthe openlpolob wedges 25.

In the case of a plurality of molds, the same stationary. member bottom 21 is used and upon which is built a series of the individual molds above described. In this manner an apparatus is provided for making a plurality of composite paving blocks at the sametime. While wedges like 25 may here again-be employed to put the molds in the closed position, use may be made of a clamp 26 with which to force in the movable side members 22 and keeping them in that position. IVhen'it is desired to open the mold, it

.is'only necessary to remove the clamp 26.

' The operation employed in making the improved composite paving block of my invention by the use of the above described apparatus is as follows:

. 'YVearing fragments of substantial granite or stone and the like of appropriate size and wearing surface are carefully placed on the the outside edges'of the mold member'2l'. In

ordert'o protect the wearing 'surface corners of the block, fragments of substantial size,

tween adj acently placed fragments should not are selected for those corners which fit exactly intothe angle formed by the corners. t is preferred that the surface areas heexceed about inch in width.

After these wearing fragments have been placed as above described, a suitable matrix, such as ordinary concrete, is poured into the mold, between and upon the individual wearing fragments. The mold is filledtothe desired depth, preferably about 6' inches. 7 Since the wearing fragmentsare approximately 3 inches in depth, it is seen that they will be securely imbedded in the concrete when the block has been thoroughly dried and hardened. The jaggered edges of the individual fragments aid materially inproviding the compactness with which the fragments are finally imbedded in the matrix. 7

If it is desired to make use of the re-enforcer 1a all that is necessary is to place this re-enforcing agent in the mold after an appropriate thickness of concrete has been poured into the mold. An ordinary piece of wire screening serves the purpose of a reenforcer very well.

After the newly formed block has been rather thoroughly dried out and hardened the wedges 25 or the clamps 26 are removed and the side members 22 are pulled back upon their hinges 23, when the paving block may very easily be withdrawn from the mold.

The improved composite paving block of my invention has many advantages. As has already been seen, the materials used are scraps gathered from granite quarries. This is a very cheap material, and moreover, offers a wearing surface that is almost incapable of duplication.

The concrete between the individual fragments may gradually wear down to a level just a triffle lower than that of the granite fragments. This will happen because the concrete is less durable than the granite. Moreover, this is an advantageous result because the wearing down of this concrete will offer a grip for the passing wheels of traffic. In other words, these relatively small re cesses willprovide an efficient friction grip between the moving wheelsv and the pavement.

A pavement made up of these blocks may readily be repaired, whenever that becomes necessary. uniform size, a worn down or otherwise injured block may readily be withdrawn and a Since the paving blocks are of to an even surface. The paving blocks are then set upon this cushion and rolled. Scarified and rolled macadam road beds readily lend themselves to the use of my improved paving block. These paving blocks are particularly adapted to be used between rails, as trolley tracks, and upon bridges. Since these blocks can be made in any desired size and shape, provision may be readily made to have the-nifit exactly and uniformly between rails, or between bridge members. This can be done in such way as not to be affected by, or to effect, the contraction and expansion of materials, due to changes in temperature and the like.

Since the wearing edges of each block are formed of granite and the blocks are placed closely together in the pavement, objectionable'grooves are not readily worn between adjacent blocks. 7 The granite edges are sufficiently strong to withstand traffic, and the joints between blocks remain intact and into the groves, making the grooves constantly larger and deeper. VVhenthe wearing edges of the blocks are formed of granite, however, these objections do not arise. The pavement surface remains smoth over very long periods.

Smoothness of pavement surface is not only assured by providing relatively narrow joints between blocks, but also by providing equally narrow joints between granite pieces going into each block. As pointed out above, these joints should preferably not exceed about inch. granite going into a composite block, adjacent pieces may advantageously contact with one another at or along their wearing edges. It is only essential that the pieces be firmly imbedded in their matrix. The pieces of granite may also advantageously be placed adjacent one another in such manner as not to provide joints running in a straight line transversely across the block, Thus, the oints are preferably made to interweave across the' face of the block.

I claim:

1. A composite paving block comprising a wearing surface composed for the most part of granite pieces of substantialsize firmly imbedded in a concrete matrix, said granite pieces being irregular in sizeand shape and having wearing surfaces that are substantially flat, said granite pieces forming the In the case of the pieces of corners and the edges of the Wearing surface side of the block in order tostrengthen the same, the ratio of the volume of granite Wearing surface to the concrete matrix being sub stantially one to one.

2. A composite paving block comprising a Wearing surface composed for the most part of granite pieces of substantial size, firmly imbedded in a reenforced concrete matrix, said granite pieces being irregular in size and shape and having Wearing surfaces that are substantially flat, said granite pieces forming the corners and the edges of the Wearing surface side of the block in order to strengthen the same, the ratio of the volume of granite Wearing surface to the concrete matrix being substantially one to one.

3. A composite paving block comprising a Wearing surface composed for the most part of granite pieces of substantial size firmly imbedded in a concrete matrix, said granite pieces being irregular in size and shape and having Wearing surfaces that are substantially flat, said granite pieces forming the corners and edges of the Wearing surface of the block, the distance between adjoining granite pieces at the Wearing surface being not more on the average than about inch, the ratio of the volume of granite Wearing surface to the concrete matrix being substantially one to one.

4. A composite paving block comprising granite pieces of substantial size firmly embedded in a concrete matrix, said granite pieces providing the block With an essentially all-granite Wearing surface whereby the presence of matrix on the Wearing facecof the block is largely avoided, and said granite pieces being so disposed in the matrix that the corners and the edges of the block normally exposed to Wear consist of granite rather than matrix, the ratio of the volume of granite Wearing surface to concrete matrix being substantially one to one, thereby pro- Ivgiding'a block of great strength and duraility.

In testimony whereof I affix my signature.

LOUIS F. HEWETT. 

